Field of the Invention
The invention relates to the field of further processing pre-products (particularly printed products in the context of print finishing). It relates to a method and a device for producing collections of printed products.
The invention also relates to a device for carrying out the method.
Discussion of Related Art
The term “direct mailing” has long been used to describe activities in which advertising pamphlets, brochures, flyers, printed sheets, product samples and the like, which usually were often enclosed (inserted) in a newspaper or magazine as enclosures for advertising purposes, are collected from several advertisers in order to make therefrom a large number of collections which each contain a printed product from a plurality of advertisers and are delivered and distributed to the recipients (for example households) in the form of a small stack.
In order to be able to better handle the individual stack-like collections of printed products during transport and distribution, it is advantageous to take measures to hold together the individual stacks.
Methods and devices for holding together stacked printed products or related products by wrapping with other holding-together elements are known from the prior art.
EP 0952006 A2 discloses a method for fabricating printed letters, an envelope, a device for fabricating the envelope as well as a method for fabricating the envelope. The application discloses the packaging of printed letters by way of a full envelope comprising a single sheet of paper or plastic which is specially cut as a packaging means, that is to say a specific packaging product. To this end, such a single sheet is said to be cut by means of a cutting unit and then folded, wherein tabs folded at fold edges can be bonded to one another by an application of adhesive.
DE 41 31 277 C1 discloses a method and a device suitable therefor, by which an object to be packaged can be united with a special packaging blank. A device is disclosed in which an object to be packaged passes from a first feeding device to a second feeding device. The second feeding device has a lower belt which is guided on one side over a roller. By virtue of a pressing device, which has a pressing roller and a guide element, a deflection of the packaging blank at the roller is intended to take place in order to guide the packaging blank in different ways onto the object to be packaged. In order to pass from the first to the second feeding device, the disclosed objects to be packaged must have a relatively high structural stiffness.
WO 2012/084494 A2 discloses a method for assembling a stack of pre-products resting loosely one on top of the other, the composition of such pre-products and a device for producing such compositions. To this end, the stack to be assembled is provided in a first step, said stack consisting of pre-products resting loosely one on top of the other, and in a second step a connecting element is fitted on an edge of the stack such that said element overlaps the two outer pre-products of the stack in an adhesive manner. This method offers reliable assembly for many applications, but requires special connecting elements which are glued.
The European patent application No. 15001321.7, which was not published before the present application, was filed on 5 May 2015 in the name of Ferag AG and discloses a device for producing collections composed of a plurality of different printed products. Some of the printed products are in each case used as a packaging element, into which the other printed products are inserted. In this way, graspable units can be produced which can easily by removed by hand from a transport container by a distributor. In contrast to previously known methods for producing such collections, in this method no special additional packaging means are required, such as films or tapes. As a result, the costs of producing collections can be lowered and the amount of waste created can be reduced. Said patent application discloses a number of methods and devices for producing such collections. One embodiment of a wrapping device suitable for this purpose has a brush roller with bristles bent in the direction of rotation, which bends upward approximately at right angles at a section of a packaging element which has been placed beforehand partially below an intermediate stack (for example of printed documents). In a subsequent step, this packaging section is bent back over the intermediate stack as soon as the packaging element and the intermediate stack enter the intermediate space between two transport belts. Such a wrapping device is suitable for a particular group of wrapping products and intermediate stacks, but under some circumstances may be difficult to control in the case of relatively thin and flexible intermediate stacks in combination with thick and stiff wrappings. Another wrapping device disclosed in the aforementioned application has rod-shaped entraining elements which are rotated about an axis of rotation oriented transversely to the movement direction of the unit consisting of an intermediate stack and packaging element. These entraining elements additionally perform an oscillating movement transversely to the conveying direction, for which a relatively complicated and/or maintenance-intensive mechanism or control system may be required.
WO 2008/074325 A1 discloses a method for wrapping a stack of sheets, brochures or the like, in which the stacks are transported at a distance one behind the other on a transport path. By means of a special swivel wheel, one wrapping sheet is pulled from a provided supply of sheets and is positioned vertically in a gap between two successive stacks. The swivel wheel then provides means which fold the sheet around the stack moving past. The complicated movement of the swivel wheel prevents a high processing speed of the stacks.